For Gigabit Ethernet, a serial communication bus is called MDIO. The bus is defined by terms of Ethernet standards Institute of Electrical and Electronics Engineers (IEEE) 802.3 of the IEEE. The MDIO is a simple double-wire serial interface that connects a management device (e.g. a Media Access Control (MAC) controller or a microprocessor) with a transceiver (e.g. a multi-port Gigabit Ethernet transceiver or a 10 Gigabit Ethernet 10 Attachment Unit Interface (10 GbE XAUI) transceiver) with management functions, so that the management device can control the transceiver and collect status information from the transceiver.
With the development of optical transmission technologies and data services, transponders are widely applied. Functions and interfaces of 100G transponders and 100G C Form-factor Pluggable (CFP) transponders have been defined by relevant international standards, but definition for the online download function of optical modules is still absent. With the growing complexity of optical module functions and the increasing improvement on optical module performance, the online upgrading ability of optical module software is critical for system equipment manufacturers. Recently, mainstream optical module manufacturers have begun defining a set of Internet Access Point (IAP) protocols based on existing hardware interfaces. However, transmission of large batch data is not taken into consideration in the protocols. In addition, in 64 bits of a frame structure (as shown in FIG. 1) in an existing MDIO interface, there are only 16 bits of effective data information which takes 25% of the whole frame length. It means that, the time for transmitting a 1 MByte file is only 4 times as much as that for downloading the effective information only. Therefore, it is low in performance and efficiency to implement the IAP protocols by existing MDIO frame structures and communication mechanisms, the download time is long, and repeated download failures occur easily.